• 한국식물병리학회지
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• 제14권5호
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• pp.393-396
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• 1998

The characteristic Ramularia type conidia of Mycosphaerella nawae were formed on naturally infected leaves. Artificial inoculation with the conidia induced typical symptom on leaves, which was not distinguishable from those of ascospore infection, which has been considered as a primary inoculum source in nature. Also the morphology of the conidia produced on PDA was not different from those formed on artificially inoculated leaves or on naturally infected leaves at later stage of symptom development. Accordingly, we report the role of the conidia as a secondary inoculum of the circular leaf spot pathogen of persimmon for the first time.

• 생명과학회지
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• 제14권4호
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• pp.689-695
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• 2004

2003년 11월 경상남도 부림면 신반리의 결구상추 재배 플라스틱 하우스내에서 늦가을부터 밑둥썩음병이 발생하여 수확기인 11월에 평균 5.3%의 발병율이 조사되었다. 이는 비교적 낮은 수치이나, 2차적으로 균핵병과 잿빛곰팡이병이 유발되어 큰 경제적 피해를 야기하였다. 이때의 병징은 아랫잎의 밑둥 부위에 수침상의 원형 내지 타원형의 담갈색 또는 갈색점무늬가 나타나고 진전되면 윗잎쪽으로 병반이 부정형으로 크게 확대되어 결국 잎이 무르게 썩고 누렇게 변하며 종이처럼 말라죽는 증상이 관찰되었다. 이에, 밑둥썩음병이 발생한 지역의 병든 식물체와 토양으로부터 병원균을 분리하였으며 이 중 병원성이 가장 강한 PY-1 균주가 Rhizoctonia solani AG1 (IB)로 동정되었다. 균사생육 최적온도는 25∼30$^{\circ}C였으며, 병원성 검정을 위해 가장 효과적인 접종원으로 검정 방법이 용이하면서도 효율적인 균사조각 부유액 접종원을 생육상내 폿트 검정용으로 선발하였고, 토양내 부생적 착생을 위한 플라스틱 하우스내 토경 재배 검정용으로는 WRSP배지 접종원을 선발하였다. 또한, 선발된 각 접종원의 최적 처리농도 및 처리량에서는 각각 균사조각 부유액 접종원의 경우, 평균 주당 51.1%의 발병도를 보인 $A_{550}$=1.0농도를 가장 적합한 처리 농도로 선발하였으며, WRSP 배지 접종원의 처리량 비교에서는 평균 주당 61.6%의 발병도를 보인 40 $m\ell$를 최적 처리량으로 선발하였다.

• Journal of Microbiology and Biotechnology
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• 제22권7호
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• pp.923-929
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• 2012

Optimization of culture conditions for L-asparaginase production by submerged fermentation of Aspergillus terreus MTCC 1782 was studied using a 3-level central composite design of response surface methodology and artificial neural network linked genetic algorithm. The artificial neural network linked genetic algorithm was found to be more efficient than response surface methodology. The experimental $_L$-asparaginase activity of 43.29 IU/ml was obtained at the optimum culture conditions of temperature $35^{\circ}C$, initial pH 6.3, inoculum size 1% (v/v), agitation rate 140 rpm, and incubation time 58.5 h of the artificial neural network linked genetic algorithm, which was close to the predicted activity of 44.38 IU/ml. Characteristics of $_L$-asparaginase production by A. terreus MTCC 1782 were studied in a 3 L bench-scale bioreactor.

• Mycobiology
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• 제35권2호
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• pp.54-61
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• 2007

Two isolates of Tricholoma matsutake T-008 and T-034, preserved in Entomopathogenic Fungal Culture Collection (EFCC) of Korea, were used in the present study. The isolates had 100% Bootstrap homology with Tricholoma matsutake U62964 and T. matsutake AB188557 and AF309538 preserved in Gene Bank of NCBI. Mycelial growth of T. matsutake was highest in TMM and MYA at $25^{\circ}C$. The highest dry wt. of mycelium was obtained after 65 days of culture, when 6 mycelial discs were inoculated in 100 ml of broth in 250 ml shaking flask. Mycelial mats were observed in clumped condition at the inoculation sites of pine forest after two weeks of inoculation. After 5 months of inoculation, mycelia mats were observed growing inside soil and walls of a few inoculation sites, while mycelial mats growth up to $5{\sim}8$ cm were observed in the roots of pine tree after 6 months. The survival rate of the inoculum was about 40% of the total inoculation sites. The survival rate was found below 20% when the mycelium was inoculated in the summer. The reasons for low survival rates of the mycelium were mainly due to dry season and the soil-borne small animals such as earthworm and mole. After one year of inoculation, no external difference was observed between the artificially inoculated mycelia and the naturally existing mycelia of T. matsutake. The present study showed that fruiting bodies of T. matsutake could be produced by artificial inoculation under the appropriate environmental conditions.

• 한국균학회지
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• 제48권4호
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• pp.499-503
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• 2020

Clubroot symptoms were frequently observed on the roots of Baecheongchae plants grown in vinyl greenhouses of a farmer located in Yangpyeong area of Korea during a disease survey in June 2019. The incidence of diseased Baecheongchae plants ranged from 30 to 90% in the vinyl greenhouses investigated. Many resting spores were found in the tissue of root galls collected. The resting spores were hyaline and spherical and measured 2.5-4.2 ㎛ in diameter. Three inoculum suspensions of resting spores prepared from the root galls were inoculated to the roots of healthy Baecheongchae plants. All the inoculum suspensions caused clubroot symptoms to appear on the roots of the inoculated Baecheongchae plants. The symptoms on the roots induced by artificial inoculation were similar to those observed in the plants of the vinyl greenhouses during the disease survey. Resting spores of the pathogen were recovered from the root galls of the inoculated plants. Three root gall isolates obtained from the inoculated plants were used for molecular identification. Comparing the isolates to the Plasmodiophora brassicae strains in GenBank, the amplification products demonstrated 100% similarity with the internal transcribed spacer (ITS2) sequences. The clubroot pathogen was identified as P. brassicae according to its morphological, pathological, and molecular characteristics. This is the first report of P. brassicae causing clubroot in Baecheongchae.

• Asian-Australasian Journal of Animal Sciences
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• 제11권1호
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• pp.13-16
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• 1998

A $2{\times}2{\times}4$ factorial study was conducted to examine the possibility of improving estimates of in vitro digestibility, using untreated (UBS) and ammonia-treated (ABS) barley straw, through homogenization of rumen fluid (RF) and by additions of urea (U) and casein (C) as N sources and Xylose + Glucose (XG) as energy sources into artificial saliva. Digestibiltiy of ABS was significantly greater than that of UBS (p < 0.001). There was a significant decrease in digestibility when additions (U, UC, UCXG) were compared with the control (p < 0.001). A 2-way interaction between RF and straw type was significant (p < 0.05) for dry matter digestibility (DMD). Homogenization of RF increased DMD of ABS (p < 0.05) whereas it decreased DMD of UBS (p > 0.05). The study showed that addition of N alone or in combination with energy sources was not better than control, rather the reverse, digestion was inhibited by a combination of U and casein (UC). It was concluded that sufficient N and branched chain fatty acids were supplied in the inoculum from sheep fed high protein grass cubes to support the growth of cellulolytic microbes during in vitro incubation. Further studies are, however, required to explore the potential of homogenization in improving the in vitro method to estimate digestibility of cereal straws.

• Fisheries and Aquatic Sciences
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• 제1권1호
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• pp.30-34
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• 1998

Rotifer culture fed on five types of artificial microparticle diets were evaluated to substitute the natural diets such as Chlorella or w-yeast. These microparticle diets including solidified blood using squid oil (SBSO), solidified blood using soybean oil (SBSB), nylon protein walled particle (NPW) simple coacervation oil capsule (SCO), complex coacervation oil capsule(CCO), were tested for the evaluation of feeding efficiency. The prepared micro particle diets had diameters ranging from 3 to 30 Jim. Rotifer culturing experiments were carried out in 3-liter beakers for 13-16 days. The initial inoculum density of rotifers was 10 ind./ml. The rotifers fed on Chlorella or $\omega-yeast$ showed maximal densities of 2,000 ind./ml in 9 days or 500 ind./ml in 7 days, respectively. Those fed on SBSO, SBSB or NPW showed maximal densities of 1568 ind./ml, 586 ind./ml or 503 ind./ml, respectively and the reproductive rates for those diets were equivalent to or better than w-yeast. However, the coacervated oil capsule showed lower maximal densities of 400 ind./ml for SCO and less than 100 ind./ml for CCO due to the unbalanced diet formulation and indigestibility.

• 식물병연구
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• 제21권3호
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• pp.231-234
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• 2015

Elsinoe fawcettii and E. australis are two currently recognized scab pathogens of citrus. E. fawcettii has at least six pathotypes while E. australis has at least two pathotypes. Colonies of E. fawcettii and E. australis do not sporulate in artificial media including potato dextrose agar (PDA). Whiteside's method has been widely used for preparing conidial inoculum in vitro. This study was carried out to develop efficient method for conidia production from artificial media. We developed a shaking method which included the following steps: 1) Colony grown on PDA was mashed with a steel spatula; 2) Mycelia fragments were cultured in 50 ml sterilized rain water in a rotary shaker-incubator (180 rpm) at $25^{\circ}C$ for 24 h: 3) The conidia suspension was filtered through two layers of cheesecloth. Average conidia production of all isolates tested using this shaking method was approximately 13.1 times higher than that from Whiteside's method in this study.

• 아시안잔디학회지
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• 제9권3호
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• pp.199-206
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• 1995

This study is aimed to clarify on the influence of cultivated conditions and fungicides on development of Rhizoetonia diseases of zoysiagrass and creeping bentgrass and results are as follows. Infection rates of disease were observed more serious when inoculum amounts were higher than low. Effects of the watering intervals on the severity of disease with artificial inoculating conditions, infection rates were higher when two days watering interval for creeping bentgrass and one day interval for zoysiagrass. Disease severity of creeping bentgrass incited by Rhizoetonia solani AG 1 (1A) was grater under conditions of double amounts of nitrogen fertilization. A posi- tive correlation was founded between the pH and disease development. The pots with pH 5 and 8 were significantly more diseased grass than those in which the pH was in 6.5. Mepronil and myclobutanil were extremely effective against brown patch of creeping bentgrass and large patch of zoysiagrass and followed by capro, and tebeonazole. Fenari was inferior effect to both diseases.

• 한국작물학회지
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• 제57권4호
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• pp.389-396
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• 2012

Melon (Cucumis melo) is an annual herbaceous plant of the family Cucurbitaceae. Phytophthora rot, caused by Phytophthora capsici is a serious threat to cucurbits crops production as it directly infects the host plant, and it is difficult to control because of variable pathogenicity. This study investigated the resistance of 450 accessions of melon germplasm against Phytophthora rot by inoculating the seedlings with sporangial suspension ($10^{5\;or\;6}$ zoosporangia/ml) of P. capsici. Disease incidence of Phytophthora rot was observed on the melon germplasm at 7-day intervals for 35 days after inoculation. Susceptible melon germplasm showed either severe symptoms of stem and root rot or death of the whole plant. Twenty out of 450 tested accessions showed less than 20% disease incidence, of which five accessions showed a high level of resistance against Phytopthtora rot. Five resistant accessions, namely IT119813, IT138016, IT174911, IT174927, and IT906998, scored 0% disease incidence under high inoculum density of P. capsici ($10^6$ zoosporangia/mL). We recommend that these candidate melon germplasm may be used as genetic resources in the breeding of melon varieties resistant to Phytophthora rot.